Safety device for sewing machines



Oct. 24, 1944. L, 0 2,361,032

SAFETY DEVICES FOR SEWING MACHINES F iled March 11, 1942 2 SheetsSh eet 1 2 Sheets-Sheet 2 Filed March 11, 1942 w M. W

Patented Oct. 24, 1944 N. J., a corporation of New Jersey Application March ll, 1942,;Serial Noil434 157. ;I wh J .6 g

This invention relates to buttonhole sewing machines more particularlyof the typ'edisclosed in the U, S." Patent to E. B. All en,No. 743,213, of Nov. 3,1903; having a vertically movable knifebar which carries a buttonhole-cutting -knifeand is given an endwise reciprocatory impulse by the" action of thefstop-motion mechanism of the machine atthe close of abutto'nhole sewing fperio' d' to out the butt'onholeslit. a I I i The knife-bar is commonlygniounted along-- side" the needle-bar in'the head of the, machine at the free end of the overhangingbracket-arm, and is connectedby mechanism with'the stopplunger such that'the downward, or work-severing; stroke of thefknife-bar is -positive and the upward, orretractin g, stroke of the knife-bar is effected through theuse ofsp'rings. In practicefiit has been found that occasionally the .buttonhole -cutting-knife is accidentally detained in its lowered} position asthe result or the work being I jammed between the sides of the buttonhole-cutting-knife and the knife-slit in the usual .lower' work-supportingplate, which jamming is p used by the insecure clamping of the workin stretched condition or the use of a dull knife. When -the buttonholescutting-knife I is not returned to its normal inoperative position at the end of the buttonhole-producing cycle, the work tin the work-clamp cannot be removed from the ,machine. inexperienced or careless, operators, when confront ed,-with this'condition; attempt to release the jammed buttonhole cutting-knife by depressing :the starting-treadle.x- When this is done fpower-is applied tothemain-shaft'and the machine inv starting. is damaged by the collision of 1 the work-clamp. withth'e buttonhole knifeholder. The primary object of the present invention is 'the provision "of'simple' means effective to prevent the starting of 'themachi'ne when'the buttonhole-cutting-knife isiheldjout of its normal retracted 'position.- 4- 1 g A further object of'the present" invention is the provision of a safety device of the above described character which is in the form of an attachment adapted to be conveniently applied to existing buttonhole sewing machines without necessitating material alterations of the ma? chine. With the above and other objects in viewgajs will hereinafter appear; the invention comprises the devices, combinations-and arrangements of parts hereinafter described in'connection with the accompanying drawings which illustrate a preferred embodiment of th'e 'invention; and in .which;l z m l 1: i'i 'lji F I Fig. 1;is a side'elevat ional viewzof'a buttonhole sewing machine. embodying the invention.

" Fig. '2' represents afragmentaryhorizontal -2--'2;Fig'. 1.

- .i ,v n -F'ig. 3 is a fragmentarysideelevational view of the sewing *machine, showing the position: of the component elements of -the buttonhole cutter -actuatingmechanismwhen the cutter is at'n-the lower end of its work-severing stroke, :and. the position of' the safetydevice inits operative or 'gua'rdingflposjfion; H 1 .v c .21: -Fi'g.'-4"represents a fragmentary vertical sectional view taken substantiallyalong the line 4 4,- Figg'l, illustrating the position of the stopcam and the stop-plunger'when-the buttonhole cutter actuating mechanism 'is' in the position -shown in'Fig.' '3;""

Fig.5 is a perspective I 'inent showing its'preferred-shape'; i 2 In the particular embodiment of the invention chosen for. the purpose 'of-thef "present "disclosure, the machine is constructed with a frame haVingabed'f I from which rises'a standard 2 "of thegoos'eneek including an overhanging arm '3" terminatingin a head 4 The sewing machine illustra'ted has substantially the-same constructiveffeature s'as are "embodied in the straightbuttonhole sewing machine disclosed-in the Allen Patent No.f 743,213, of Novn 3;; 1903. Such' a machine has the 'usual stitch-forming mechanismincluding a needle 5 and a complemental loop-taker 6; the" period of operation of which is' controlled bythe usual stop-motion device including a "tilting stop-motion lever 1 which is pivoted 'on truhnion-screws'8 to a frame-bracket -9 secured 'tothe stand'ard2.- The stop-motion sectional view taken substantially alongthe line lever l-fhas'; journ'aled" therein an upwardly spring influenced stop-plunger I0 which, when the stop-lever! is shifted to stopping position, Fig.1, is first depr essed by the eccentric plungerdepressing portion l'l 'of a fstop-caml2 eonnectedfas shown'in theAllenet aLPatent No."

139153310, o J ne 27,1933; through speed-reduction gearing f3} I 14 to the usual belt-driven mainor'arm-sh'aft 15 andthenprojected by the spring I6 as the stop notch Win" the cam l2 comes into register with the stop-plunger l0.

, To provide for swinging the stop-motion lever 1" out of vertical stopping"p osition tostart the buttonhole stitching cycle; the stop-motion"le'- ver is provided with 'a forwardly extending arm 18 fromthe free endof which depends a treadleview of-the safety ele- I operated rod 19 having in its side a notch 20 adapted to receive a spring-biased latch-lever 2|. The latch-lever 2| is fulcrumed at 22 to the under side of the bed I and carries an adjustable tripping point 23 which is engaged by a tripping point (not shown) secured on the usual feed-wheel 24 to stop the sewing mechanism at the end of ahuttonhole sewing operation. The iced-wheel 24 is secured'on the lower end of a vertical feed-shaft 25, which'feed-shalft is given one revolution per buttonhole-producing cycle through the usual gear-train connections" 26 actuated by the arm-shaft a'liQ'The wnrk-- clamp, indicated as 21, is connected to the feed :15 ing mechanism to assist in'producing the huttone wheel24 so as to be shifted :relativeto the stitch-'- hole.

-and swings -the trip+lever 49 sufliciently to remove the extension 48 from underthe arm 41 of the latch-lever 44, whereupon the latch 44 is drawn over by the spring 46 so that its shoulder 3A5 engages underzthe screw-pin and couples the lever 32 to the lever 39. This cam 53 passes The buttonhole cutting mechanism icomprises".

a vertically reciprocatory knife 28 fixed ,to a, knife-holder 29 carried at thelower end of a cut-' zter-rhar rsnrjournaled ior iendwise reciprocation in the head 4 and connected by a link 3| its the the mutter-hernear end of :the cutter-lever -rrorwa'rd enrllofmgcutter-devter 32 tulcmmed at 33 to theiarm 133ml biased byaspnng .34 to :raise .22 carries'ascrew apindiwhichrextendslaterally through a vertical slot 38 in a link .flp

at .48 its theflontzendnbedever 39. The lever :the :standand;2:end informant its-rear end with naslot .41 entenedwby alatenalstud 42 fixed to'the stop-plun er Ml; Pivoted-zat 43 on the link 3?! ,is :a latch-lever dormedrat :its upper-:endwith a shoulder 45 which is normally rhel'dhyqaspring 46 -in :thepositicnashown .in Fig. 3. in engagement --with=and below screw-pin .35, to couple the lever 39 to theilever -42. -When. in the position 89-.zis' 'iumrmnedrintermcdiate :its ends at -40 to shown-in Elia-:3, the latch-lever s44. completes :tnainpf {actuating connections between the stop-plunger l0 and the cutter-bar :30' and, in

efiect; provides "a. positive-drivabetween the stopcam l2 and the huttonholee-cutting-kni-fe .so that the latter is positively actuated to .sever the .work whenlthestqp-plunger depressed by zthestopcam-:2. the-understood that the work-clamp isshif-ted-relati-vetotheneedle to assist in efeienting the pnoduction .oi the -buttonhole.--;To prevent accidental operation of the buttonhole cutting mechanism when .the .evork-clamp is aporsitioned :beneath the buttonhole-voutting-eknile 28 and thereby: ause damage the knife, means substantially .thessame as that disclosed :-in the Genre-ll, et :aL, Patent JNQ. 1,9363%; .Nov. .21, .1933, is provided .to uncomile .the ,latch-lever -44 from beneath the .sorew pin .35,!thus renderingthe actuating? mechanism tier .the hnttonhole-cutiting-knife inoperative. EIIe...this end. he latch- .lever 4.4 is prederalcly termed V with 'alateral arm the {follower 52 and releases th trip-lever 49 'which isthen swung by its spring 54 so that its extension 48 bears against the sideof the lateral When the sewing operation is completed, the depression of the stop-plunger H) by the eccentric portion 1-! .of the .stop-cam-JZ causes the levers 39 !and .32 -lac-move .to. their positions shown ;in'- Fig. .3,. as .the huttonhole-cutting-impulse is imparted to .the knife 28. This impulse raises the lateral arm :4Jaof the latchlever above the .tripsarmaextension 48 which .promptlymoves under the same. 1 On the :recovery motion of the ,parts, the .lateral arm A] .strikes downwardly upon the trip-armsextension 48 and efiects an unceupling of the lever-38 from the lever 32 as the cutter-bar. 30 ismoving upwardly and before the cutter-bar reached. the upper limit of its movement.

It ,will he understood from the above that durin substantially the entire huttonhole-producing-cycle the levers 32 .and 3B of the .buttonhole actuating mechanism .are .uncoupled and that for onlya shortperiod of timeat theend of the cycle :the said levers "are coupled together. Operation of thej.butt'onhole cuttin wmechanism is thereby prevented during the time that the work-clamp is positioned ibenea'th the'buttonhole knife 28.

In practice',fit has been found that when the knife "becomes dull or, when a material having 5 a considerable amount of stretch ls being buttonholedythe work occasionallyls-notcut cleanly'hy the knife and-"is pulled into the knife slo tprovided in the -lower work-supporting plate, thereby wedgingthe knife the slot and preventing .150 springs 16 and "3-4 from raising thelmife'upweirdly into retracted position. When this occurs the 'machine's'tops'at the-end of the'button f-hole-stitching-cycle'with thehuttonhole-cuttingknife in the work. @bviously, with the knife in 55 this abnormal TDOSitiUll, :the work cannot be re- 41 which at .times rests .upon .an upturned .end-

extension-A8 of a .trip lever fl .Iulcmnned at .50 to the underside. of a horizontal lug 5.! .on the standard 22. .lmhev modem .carries .a follower .52 which is yieldinaly snaintainedrin the .pathef a :cam .53 @Ilft-hQ feed-shaft 25b .a coil-spring .54. Whenthemachineis at rest, the parts are'in thepositions .shownrin Fig.- l with the latch-arm M nesting :np n the. trip-lever (extension 48 and the.v cutter levter .32 .uncoupled from its actuating .lever..39. H I

Whenithe .stop-motionleiierfl is tilted .to start the machine, thestQp-Pmnser ID .is tilted out of the stop-notch thin the stop-cam 12 .and rises sli htly under .thelinnuence .of .the spring 1-6. This rise: ot the lston plunfler rimmed wfrom'zthe work-iclarnp. In the event an inexperienced zor'careless operator releases the stop-motion mechanism to apply powerto-lthe machine in :anattempt to elevate the button- :holewutting-kniie, the work-.clampZ-I is shifted atclative'to [the rneodle rand-collides with-the knifeholder 29 which, .ofcourse, .has not been elevated by the application of power .tothe machine.

To prevent vthe release of the stop-motion mechanismto .start the machine when rthe button holeecutting-knife .28 is .held in the work, there. is provided .a safety device connected .to he peratedhy the actuating connections between the stop-plunger 1.0. and the lhuttonhole knifebar 30. As clearly shown in Figs. 1 and 5, the safety device comprises. an attachment in the form ofv .a lever .55 .adapted .to be tulcrumed intermediate, .its .ends upon the existing shoulderscrew 5.6- withwhich, the machine .is equipped.

L0 swings ll-.5 The .forwardend .of the .saiety lever 55 is pref:

1 cutter-lever'32. The rear-end of 55 is inclined, as at59, and is ..-end of the stop-motion-lever is traveling through all but the last e'rably formed with an'open ended slot,51pro viding a bifurcated extremity adapted to straddle thereduced cylindrical portion of a nut 58 .(Fig 2) adapted for locking the screw-pin 35 in the adaptedto be swung into. the'path'of movementof the upper T when .the'comI- ponent parts of the buttonholecutting mechanism are in the positions illustrated in .Fig. 3.

The operationofthe safety-lever 55 is as fol;-

- lows: When the stop-plunger lO-is positioned at its upper .limit, which is the case when the ,ma-

chine is at rest (Fig. 1):, or-when the-machine portion of the buttonhole-producing-cycle, the safety lever 55 is positioned so that its inner end 59 is located at a level above the'upper end of the stop-motion;- lever 7. When the stop-motion lever I is-re leased to swin into its vertical stop-position and thestop-plunger I is depressed by the eccentric .portion ll of the stop-cam l2, the screw-pin35 the safety levercarried by the cutter-lever 32 is raised upwardly V by. the. latch 44, link 31* and lever. 39. In;.its ,movementupwardly, thescrew-pin35 swings the; safety lever 55 about its fulcrum-stud 55in such a way as to lower the inner end 59 of the safety 'lever 55 into the path of movement of the stop." motion lever. When thesafety lever is in this position, the stop-motion lever cannot be swung the machine cannot bestarted; Having this in out ofits vertical stop-pOsition. 'In other words.

mind, it will be understood thatlshould the buttonhole-cutting-knife 28 be held in its lowered work-severing position,

case the safety lever 55 swinging of the stop-motion-lever I out of its} vertical stopping position to start the machine.

From the above description, it will be understood that a simple and eifective means has been devised which will preclude the starting of the machine during the time that the buttonholecutting-knife is in a position such that the work-' clamp Will collide with the knife-holder and damage the machine. It will be appreciated also that the safety device in question is in the form the parts will be maintained in the position shown in Fig. 3, in which will prevent the manual? of an attachment which can be readily applied to existing machines by providing a nut 58 having a reduced cylindrical portion and a slightly longer shoulder-screw 56. I While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification, without departing from the spirit of the invention. I to be limited to the precise details of construction set forth, but desire to avail myself of such variation and modifications as come within the scope of the appended claims.

Having thus set forth the nature tion what I claim herein is:

of the inven- 1. A group-stitch sewing .machine havijriig stitching devices, a work-clamp, a work-cutting knife normally in retracted position during the stitching operation, a stop-motion device including a notched cam, a movable stop-motion lever having a running position and a stop-position and a stop-plunger carried by said lever and adapted to enter the notch in said cam to stop the machine, mechanism operatively connecting said work-cutting knife to said stop-plunger, and an element directly connected to said mechanism to move into the path of said stop-motion lever for preventing movement of the latter into its connected to said therefore do not wish running position when said work-cutting-"knife is outof its normally retracted-position. V.

2. A group-stitch .sewing machine having stitching devices, a work-clamp, a work-cutting knife normally in elevated positionduring the stitching operation, a stop-motion device including-a notched cam, a movablejstop-motion lever having a running positionand a stopposition and a stop-plunger carried by said lever and adapted toenter the notch in said cam to stop .the machine, mechanism operatively ,connecting said work-cutting knife to said stop-plunger, and a pivotal member connected directlytoone .of the component elements of said. mechanism and operated thereby tomove into the-path; of said stop-motion lever and of the same into its running-position when said work-cuttingknife is below itsnormal or. elevated position, 1 h h v 3. A group-stitch sewing; machine having stitching devices," a work-clamp, a work-cutting knife normally in elevated position during" the stitching operation, a stop-motion device including a notched cam, a having a running position and astop position, and a-stop-plunger carried by said lever and adaptedto enter thetnotch in said cam to stop the machine, mechanism operatively connecting said work-cuttingknife to said stop-plunger, and a single pivotally supported lever connected at one end to one of the component: elements of said mechanism and operated thereby so that the other end of the lever moves into the path of said stop-motion lever and prevent movement of the same into its running po'sition when said workcutting knife isbelow. its normaLorelevated position.

4. A group-stitch sewing machine having in combination, a frame including a bracket-arm terminating in a head, complemental stitching instrumentalities, a work-clamp, a work-cutting knife normally in elevated position during the stitching operation, a bar journaled in said head and carrying said knife, a stop-motion device including a notched cam, a tilting stop-motion lever having a running position and a stop position, and a stop-plunger carried by said lever and adapted to enter the notch in said cam to stop the machine, mechanism operatively connecting said work-cutting knife to said stop-plunger, said mechanism including a cutter-lever connected by a link to said knifebar, and a member directly cutter-lever and operated thereby to move into the path of said stop-motion lever for preventing movement of the latter into its running position when said work-cutting knife is out of its normal or elevated position.

5. In a sewing machine of the buttonhole making type having a main-shaft, sewing and workstop-motion device including a manually shiftable trol the period of operation of said main-shaft, and a work-cutting knife at rest during the sewing operation with mechanism to operate it automatically; the provision of a single lever-member knife is moved out of its at rest position.

6. A buttonhole sewing machine having, in combination, a frame including a bracket-arm terminating in a head, a work-cutting knife no prevent movement movable, stop-motion lever,

mally in elevated position during the stitching operation, a bar journaled in said head and carry- "ing' said-knife, a'stop-motiondevice having a running position and a stop position adaptedto stop the machine in a definitexst'op -position,

mechanism operatively connecting said work c'utting knife to said stop-motion device, said mechanism including a pivotally mounted lever,' and a member fulcrumed upon saidframe-and having mally in'elevated position during the stitchinging said knife,

one of its ends shaped toengage said pivotallv' mounted lever and be oscillatedthereby about its fulcrum so that the other end of said member moves into a positionsuchthat it will prevent movement of the stop motiond'ev'ice into its running position-when said work-cutting knifeis out of its normalor elevated position.

'7. A buttonhole sewing machine' having, in combination, a frame includingabrackeiwai'm terminating in a head, a workcutting knife noroperation, a bar journaled in said head and carrya stop-motion device including a notched cam, a movable 'stop-m'otion'lever hav- "ing a" running position and a'stop position, and

a stop-plunger carried by said lever and adapted "ter into its running position when said work-cu't-' to-enterthe notch "in said ham to stop the "machine; mechanism operatively connecting said work-cutting knife to 'said stobmlunger, said mechanism including a pivotally mounted cutterlever provided witha screw-pinjan d a member fulcrumed on said frame and slotted at one end to engage said screw-pin and be operated bysaid cutter lever to move into the path of said stopmotionlever for preventing movement of the latting knife is-out of its normalor elevated position. i

can: nose 8. A safety device adapted for use on aisewing machine having a work-cutting knife normally 'in'elevated position during the stitching operation, a stop-motion device including a movable stop-motion lever having a running position and -a stop position, and mechanism connecting said iwork-cutting knife for actuation by said stopmotion device, said safety device comprising a lever-member adapted to be pivotally supported for limited oscillatory movements, said levermember having one of its ends slotted to'engage one of the component elements of said mechanism whereby the other end of said lever-member is 'moved into the path of said stop-motion lever for 15 preventing movement of the latter into its running position when the work-cutting knife is below the normal or elevated position.

9. A safety attachment adapted for use on a sewing machine having a work-cutting knife nor- 20 mally in elevated position during the stitching operation, a stop-motion device including a'movable stop-motion lever having a running position and a stop position, and mechanism connecting said work-cutting knife for actuation by said stop- 

